package com.happymmall.dao;

import com.happymmall.util.DruidUtils;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

public class BaseDao {

    private static String driver;
    private static String url;
    private static String username;
    private static String password;

    //    // 静态代码块，类加载的时候就启动了
//    static {
//        Properties properties = new Properties();
//        // 通过类加载器获得对应的资源
//        InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
//        try {
//            properties.load(is);
//        } catch (IOException e) {
//            throw new RuntimeException(e);
//        }
//        //要和properties文件里的字段一模一样
//        driver = properties.getProperty("driver");
//        url = properties.getProperty("url");
//        username = properties.getProperty("username");
//        password = properties.getProperty("password");
//
//    }
    public static Connection getConnection() throws SQLException {
        // 替换原有的DriverManager获取方式
        return DruidUtils.getConnection();
    }

    // 编写查询公共类
    public static ResultSet execute(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet, String sql, Object[] params) throws SQLException {
        // 预编译的sql，在后面直接执行就可以了
        preparedStatement = connection.prepareStatement(sql);
        for (int i = 0; i < params.length; i++) {
            // setObject 占位符从1开始，但是我们的数组是从0开始
            preparedStatement.setObject(i + 1, params[i]);
        }
        resultSet = preparedStatement.executeQuery();
        return resultSet;

    }

    // 编写增删改公共方法
    public static int executeUpdate(Connection connection, String sql, Object[] params, PreparedStatement preparedStatement) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);
        for (int i = 0; i < params.length; i++) {
            // setObject 占位符从1开始，但是我们的数组是从0开始
            preparedStatement.setObject(i + 1, params[i]);
        }
        int updateRows = preparedStatement.executeUpdate();
        return updateRows;
    }


    // 释放资源

    public static boolean closeResource(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet) {
        boolean flag = true;
        if (resultSet != null) {
            try {
                resultSet.close();
                // GC回收
                resultSet = null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }
        if (preparedStatement != null) {
            try {
                preparedStatement.close();
                // GC回收
                preparedStatement = null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }
        if (connection != null) {
            try {
                connection.close();
                // GC回收
                connection = null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }
        return flag;
    }

}
